Method of polymerizing rosin and product made thereby



Patented July 1, 11.941-` C. almerand Carlisle H. Bibb, Pensacola, Fla., assignors to Newport Industriesflnc., Pen- A l saoola, Fla., a corporation of Delaware.

Application September 28, 1938. Serial No. 232,078 'A f LY (c1. zeit-smi This invention relates to aY method of polyy No Drawing.

`21A claims.

merizing rosin and to the product made thereby- More particularly, this invention relatsto the polymerization o f rosin bylmeans'of zinc chlo ride under anhydrous conditions and recovering' l5 same color grade as that of the original rosin.

' the partially polymerized rosinwithout lthev use s The modifications of the -prior art processes necof -fractional distillation` to separate lower melting point constituents from the higher melting point rosin acids.

Accordingto the method'of our present invention, not only may themelting point `of rosin'be increased, but this can be done with little orno sacrice of the acid number and 'with anv actual improvement, if desired, in the color of rosin; where a dark rosin is used asthe vstarting material. If a pale rosin is treated in accordance with our process, the product is substantially as pale as thev starting rosin. F1'1rthermore.,'

our .product is'entirely-free i'rom 'zinc compounds resultingfrom the useof zinc chloride as `the polymerization catalyst. I

In contrast to this feature of our invention, all methods heretoforep'roposed for increasing the .melting point 'of rosin by 'means-of catalytic polymerization have had'y the common objection `0f leaving a portion of the polymerizing materials chemically combined in the rosin. In processes employing concentrated sulfuric. acid as the polymerizing. agent, as in the Morton Patent No. 2,017,866 and the Rummelsburg' Patent No.

2,108,928, for example, the 'rosin product con-'f tains combined sulfur, -which forms hydrogen suliide and sulfur dioxide Jwhen the rosinis sub,-

sequently used yfor soap, varnish, ester gum and other purposes.

In the shnorf Patent No. 2,074,192, corresponding metal resinates are formedl 'in' amounts; v depending upon the amount of polymerization agent used and the conditions of operation. We have now'discovered that of the metallic halides referred to in this patent, zinc halides are the onlylones that can be readily and completely separated from the treated rosin. .The process for accomplishing the complete removall of zinc from the partially polymerized rosin vconstitutes an important part of ourpresent invention.

If, in carrying out the processes of prior patents 'above referred to, it is desired tomaintain or improve the color, as well "as substantially rincrease the melting point of the rosin treated, it 50 is invariably done at aconsiderable sacriiice 'in yield and'also reduction in'other' values of the rosin, such as acid value. vW'e have discovered that undery proper conditions zinochlorlde lsv. oapabieof giving 100% yield of progiuot or sub- 55 stantially the same acid value and with an increase in melting point' of from'15 to 25 C.,

(measured by the capillary tube method), whilel at the sameA time retaining substantially the essary. to accomplish this result also ,form a part of our presentinvention.

The patent to-Schnorf, No. 2,074,192 quite evil dently refers to the treatment off dark or crude rosin as the starting'material, since the patent vdescribes the treated rosin as being no2 black distillation, 4a-.polymerized rosin of substantially higher `melting point than that of the starting y lrosin.

The treatment of pale wood or gum rosin to obtain directly a partially polymerized rosin product oi' substantially equivalent color grade and of greatly increased melting point is an important object. of this invention. In our process, starting with WW wood rosin, we get a palenishedproduct with an increasein melting point of from 15 ,to 20 C. without subjecting the rosin 3 0 to partial, distillation, and we produce no soft materialsA and maintain. the original acid value.'A

Our studiesof the optical properties o partially polymerized rosins, produced by our process using zinc chldride, have led to interesting conclusions. 'By way of example, WW rosin having initially a'rotation of -13 was' partially I polymerized l'by zinc-chloride to give -a product i( having a melting point of176" C. and a rotation Fractional distillation under reduced 40 pressure 'yielded 9.45% pale middle fraction (after taking oi small amounts of soft heads) having an acid value lof 177 and a rotation of\ +20,and a 35% non-volatile residue of dibasic rosin acid of melting point 120 C. and rotation 5 .-40, an rotation tests being taken in 10%' pe- Y troleum naphtha solution. f

Fieser and Campbell. 'in the Journal ot the American lChemical Society. January 1938,-

clearly show that the only forms of rosin acids, obtained by the chemical processing of abietic acid, which have positive optical rotation are hy-L droxy abietic, dehydrogenated abietic and hydrogenated abietic acid. Since hydroxy abietic acid could not be formed by our process, the

foregoing 'optical rotation results clearly indicate that in-our polymerization process,- the zinc I chloride acts as a simultaneous hydrogenation4 and dehydrogenation catalyst to form what is known as disproportionated abietic acid, i. e. both dehydro and dihydro abietic acid in admixturei,

Nickel, platinum and palladium, and coppery or ucts are free from zinc compounds resulting from the use ci' zinc chloride and have substantially higher .melting points and not substantially lower l zinc chromates have previously been suggested l as catalysts to produce this simultaneous hyldrogenation and dehydrogenation, but to the best of our knowledge the use of zinc chloride for this purpose has not been heretofore known.

Heat treatment alone of the rosin produces 'this same eilect, as shown in the Logan Patents Nos.

1,643,276 and 1,807,483 and proved by Fleck and Palkin V(Journal 'ofv the American AChemicall Society,flpril 1938).

Thus, in practicing the method of our invention, using zinc chloride as'catalyst, we obtain twoeiects, polymerization and disproportionatlon, but neither to completion. We may, therefore, -further process the lpartially polymerized rosin by subjecting `it to heat treatment,`as for instance by heating the rosiny for 1 to 6 hours at between 250-and 300 C., and'carry the dehydrogenation-hydrogenation reaction still further. This subsequent treatment enables us' to destroy traces of color bodies formed in the polymerization process to impart to the-rosin product maxi- Y polymerization reaction.

troleu'm solvents is equally effective. In fact any acid values than the starting rosin.

Other and further Vimportant objects of this invention will become apparent from the following description and appended claims. f

Our method .of obtaining a rosin of higher melting point than the starting material involves the partial polymerization of rosin, either gum or wood, by the use of a zinc halide as the polymerization catalyst.. 'The removal oi any zinc from thel rosin product i'sbased upon thediscovery that the water soluble zinc salts of the 'watersoluble organic or inorganic 'acids'stronger than abietic acid can `be readily and completely lseparated `from solutions of the polymerized rosin. Thus, by simply reacting the zincresinate present in the solution of `the` partially polymerized rosin with an aqueous` solution of an acid stronger than abietic acid, such as formic,

acetic, sulfuric or hydrochloric acids, followed byA water washing, the zinc salt of the corresponding stronger acid used can be completely extracted from the rosin product. 1

'The solvent preferably ,used is-a petroleum h I' drocarbon boiling between 105 and 140". C. Such .a solvent has been arbitrarily selected primarily because the reflux temperature of the rosin solution, using such a solvent and at the desired rosin concentration, adords an easy control of the A wide range of peorganic solvent that is inert during the reaction, i. e. does not itself become polymerized or chemically react with the rosin, may be-employed, in-

duced, which is very stable as tocolor when made into a varnish, ester gum or the like, and there is alsoproduced a residue ci.4 pale color, grading K or better on the standard color scale, of a melting point of 110 C. or higher and consisting largely of polybasic rosin acids.

It is therefore an important object of this invention to provide a method of increasing the melting point of rosin, either gum or wood and either dark or pale, while at the same time maintaining substantially the same acid value of the starting rosin and obtaining yieldsapproaching 100%. i

It is a further important object of this' invention to provide a method of polymerizing rosin by the action of heat and a zinc halide and under strictly anhydrous conditions to prevent degradation in the color of the rosin. Y

It is a further important object of this invention to provide a process whereby a partially polymerized rosin .may-be obtained 'entirely free from zinc compounds introduced into the rosin by zinc chloride used as the polymerization catalyst.

It isf a further important object of this invention to provide a process of treating rosin that -includes both partial polymerization and partial dehydrogenation and hydrogenati'on of the abietic acid to give a rosin product of high melting point and possessing a high degree-of a color stability when made into a varnish, ester gum or the like. l

It is a further important object of this invention to provide the wood rosin products resulting from the processes described herein, which prodcluding aromatic hydrocarbonsA such as benzene,

.toluene and the like.

While the polymerization of vthe rosin can be conducted in the absence of any solvent, this is not practical because in order to obtainthe most favorable temperature conditions for preventing color degradation, say not exceeding 140 C., the polymerized rosin toward 'the end of the'reaction would be too viscous to permit the extensive contact with the catalyst that is required for efilcient carrying out of our process'. The yuse of a solvent is therefore, important to the Obtaining of the desired improvements in our process.

The concentration of rosin in the solvent is also important. If the concentration of rosin is less than'about 50% of rosin by weight ofthe solution, the polymerizing effect is not great. Even 'in concentrations below 60%, there is a reduction in the polymerizing effect. We have found that at between 62 and '70% concentration of rosin in the solution, the most favorable effects as regards color, maximum polymerization, acid value retention and the like are realized.

We have discovered that the prevention of color degradation using zinc chloride as the polymerizing agent is controlled by (l) maintenance 'of a suitable temperature of the reaction, and

(2) maintenance of anhydrous conditions. We fully recognize that the desirability of employing approximately anhydrous conditions for polymerization reactions using zinc chloride has been be removed by reiluxing over a reasonable period.

. not only must anhydrous conditions be present' initially Vbut they must be maintained by proper 'The presence OfoXygen'ated, bodies also interretluxthe rosin solution remove as little as. 0.2% of water (which amount would normallybe `present inv rosin recovered by steam distillation from solvent and would remain dissolved upon; f

resolution .of such rosin to a concentration `of 50% or higher without giving a cloudy solution) in orderto secure the desired anhydrous conditions; -For example, if a 66%% petroleum solutionof commercial WW wood' rosin having a melting point of 60 C.: and an acid value of 168 is heated for 12 :to ,'16 hours with 11/2%` of dry` granular zinc chloride at 1 28 138 C., theresultallumeop.'`V I3 in 1770 gals. .of petroleum solvent? boiling between by weight.

ing rosin, after recovery and after being freed of zinc resinate, will have a melting rpoint of 76 C., an acid value of 166 and color K. If the same operation be repeated, but 'if before adding` the catalyst we secure anhydrous'conditions by reiluxing-'the rosin solutiomtnrough a condenser containing aI water trap and separating 0.2%

water, the resultingrosin will have the same increase'lnl melting point but will grade WGH- and also have an .ac'iclyvalue of .166.r Thus, arosin solution, for the purposes of thisinvention, is not anhydrous unless it is free ofl all- 'water that can If the reaction be carried out at 145 C. or

-over, water is formed, the acid value of the recovered rosin will drop to 153 andthe color will be I or K. We have, therefore,` discovered that temperaturel` control.'v At the higher, reaction temperatures the action of the polymerizing catalyst is also that of decarboxylation and bothwater and hydrochloric acid are formed. We believe that hydrochloric acid, which would be formed lby hydrolysis of zinc chloride, is 'the cause. of thediscoloratiomand hydrochloric acid is not formed unless water'is initially present or .I

isgenerated during the polymerization reaction. Consequently, we carry out our polymerization under such conditions Ithat not 'more than the minimum amount of hydrochloric acid is formed.

No matter what the starting grade of rosin, thecolor can be substantially maintained 'after the partial polymerization treatment if the above Aconditions are followed. However, in order to obtain an-A approximately 100% yield' or equivalent color grade, together with increase in melt lng point of around 15 C., the kind and graleof ered that no rosin containing appreciable quanti- -drated.' This mayI beaccomplished byplacing 'e -slowlyin order t6 avoid undue boiling and `s ub,

sequent danger of the solution 'surging `over the' top of thecontaining vessel.y

Since exposure of zinc chlorideto -humid air causes it to pick up considerablev moisture.- such exposure of the yzinc chloride prior to actualuse is to be avoided. V The amount of zincchlorideadde'd corresponds wlth 11/2%. by weightl of the rosin undergoing treatment. '.With 'this percentage of catalyst, best results are obtained by `carrying out the reaction 25.

for 12 to 16 hours. The reaction timewill vary y somewhat with the proportion oi'catalyst used.

'The temperature of the reaction mass during che entire period is kept at about 128 to 138`C.,.

' rosin is also more important. Wezhave discovthwater *Settles ties of oxygenated materials Acan be treated by this process and retaintheoriginal color grade Without sustaining loss as dark resin. 4For example, WG to WW grade wood or gum rosins or equivalent as regard presence of oxygenated .bodies will give substantially 100% yields of partially 4polymerized rosins of say N to WW color.

feres with the polymerization to some extent. For example, an M grade fullers earth purified Wood vrosingave 94% yield, K+ grade, with only 10C.` increase in melting point, and K grade furfural purified wood rosin vgave 85% yield I 6 `grade withonly 5 C. increase in melting point using exactly the same-procedure as gave 99% yield, WG grade, with 15.` C. increase in melting point starting with fullers'earth purified WW grade Woo'd'rcsin.

'Ihel following example will illustrate a pref ierred embodiment of our invention:

seco pounds-df WW `wood rosin are dissolved 75 washes as well as the lorjust'under theboiling point of thesolutionJ- s At the end of the reaction time, the hot rosin solutionl is washed as follows, maintaining theA rosin solution at about t0 80 C.Z v L Wasnv volume l 1st l 400 gals. water. -l y 2d.. l 120 gals. 1.5% sulfuric acid.

. 400galafwater. L

Dun f Do.

ny ,undssolved "zinc chloride -and traces of "tarry matter dissolve vin the irst wash water.A

The fifth wash -should befreeI of zinc compounds but washing s hould be carried-'out-until tests' show the absence'of zinc compounds and also the'. absence of chlorides and sulfatesl The washing step is preferably/carried outji-n` thev reaction vessel by mechanical agitation'. Since the solution contains no emulsifying agents,

the agitation.

The washed rosin solution is next transferred toA a suitable still, where-the solvent is evapo- Y l' rated 01T by passing dry steam through the solu.

tion in the still. Final steaming at 210 to 220 C. still temperature ls recommended. It is pos sible to use lower finishing temperatures, but the rosin is q uite viscous even at C. with the higher melting types resulting from the poly. merization reaction. To obtain the desired melting point of 76 to 77 C., it is necessary that all traces of solvent rbe steamed off of the rosin.

The foregoing process hasreadily produced a. rosin ofthe following properties:

Color WG l lMelting point 75 to 80 C. Acid value l 164'to 167 Rotation -4 to '8 Asll Less than 0.01%

In stating jthe'melting pointoi` rosin or any of the rosin products described herein, it will be understood that such melting points have-been determined by the capillary tube method. For

out rapidly upon cessation of the sake of comparison, howeverythe following relationship exists between the capillary tube method and the so-called dro'p method, referred to in the Schnorf rPatent No. 2,074,192:-

'16 c. (drop) equa1s 52 capiuary tube 76- C capillary 'tube equals 100 C. drop method Higher meltingpoint rosin is obtainableat the expense of using more catalyst and at a sacriiice incolor grade and a lowering of 'acid value. The reaction time can be shortened to from 4 to 8 hours by increasing the proportion of catalyst used to a maximum of 3%, and thecolor grade can be maintained under these conditions.. In general, however, longer time of reaction with any given amount of catalyst tends to give a a preferred embodiment of our invention as applied to FF wood rosin as the starting material:

. Example 2 FF wood'v rosin', having'a melting polnto'f 53? C., and an'acid value of 153, is subjected tothe action of zinc chloride, using 11/2% of zinc chlorideby Weight of the rosin-and a rosin solution containing 66% of rosin by Weight, the same as described in Example 1. A 100% yield o f partially polymerized rosin i's obtained, having the same color grade as the starting rosin and having a melting point of 68.5 C. and an acid "value of 148. `If, however, before washing out any combinedain'c, the rosin solution is diluted from 66% concentration-down to 12% to 15% concentration, there, occurs a precipitation of higher melting point; lower grade and lower acid value in the polymerized product. 11/ of catalyst is the practical minimum in any case.

Hot water is recommended in the washing operation because in view of the h'igh'rosin concentration it is obviously necessary that/the r'osin solution be kept fluid. As an alternativeprocedure, the rosin solution at the-end of the re action may be diluted and the washing con' ducted with hot or cold water. f

If it is, desired to secure the maximum amount of disproportionation of the rosin acid,.the partially polymerized-.rosin may be heat treated at 260 to 270-C. for about 2'to 3 hours, in accordance with the methodl of the Logan Patent No. 1,807,483, dated May 26, 1931.- This treatment alone will improve the color a grade lor more on the color scale, but will also lower the acid value somewhat and decrease the melting point several degrees C., both being the eiiect of unavoidable decarboxylation during the hydrogenation dehyfdrogenation byheat. After'the rosin has been subjected tothe action of heat and zinc chloride in accordance with the procedure of the foregoing example and heat treated as just described, the resulting product i-s then fractionally distilled under reduced pressure to ,separate as the first fraction about 12%" of a yellow colored about 8% of nigre, which may be removed to givea-partially polymerized rosin grading. after recovery, a brighter colored FF.

When this partially polymerized rosin is given successive polymerization treatments in the same manner, the second treatment results in a G grade rosin having a melting point of 76.5 C. and an acid value of 147.5; the' third treatment also gives a, Gl grade rosin, but having a melting .point of 80 c. and an acid value of 146, with' a of 66C. and an acid value of 151.

semi-solid rosin of acid value about 88 and optical rotation of' +48, andas a second fraction about 121/'% of pale (X+) rosin, having a melting point of about 53 C., acid value of 158 and rotation of +31. The residue Will have a melting point of 95 to 100 C., a color-of N grade or better A large variation in the method is, therefore,

possible. This partially purified, partially polymerized rosin 4can be further rened by treat- `ment with selective solvents, such as furfural.

or by means of fullers earth or equivalent de- .colorizing material. 'A partially polymerized rosin grading FF and having amelting point of 72 C. Aand an'acd value of 147, was bleached to M grade rosin having a melting point of 70 C.

' andan acid value of 155, by the use of fullers and an acid value of about -145 and an optical" rotation of -11.

If it be desired to convert the maximum amount of the starting ro'sinto a polymerized rosin, the time of4 reaction, using 11/2% of zinc v chloride catalyst, is simply increased. A reaction period of about 90 hours results in agrade Ito' K rosin, having an acid value of 148, a melting point of `90" C. and an" optical rotation of 25. This product upon vacuum fractionation and the removal of 10% of soft material, having an acid value of 77.5 and a "rotation of +5,l gives a, residue ,earth In general, -the polymerized dark rosins do not decolorize as readily as natural rosin, so that for practical economical purposes we prefer to conduct our polymerizing reaction on already highly purified rosin. Y

Ihe various products produced in accordance with the processes of our invention as herein described may be distinguished from heretofore known products in several. ways. With respect y to the partially polymerized rosin product resulting directly from the polymerized step using zinc chloride, this product is distinguished from that rosin with a melting point of 109 C., an acid value of 15,8, a rotation of -27 and a color 'grading I to K.

While the novel features of our process have 'been described principally as applied to pal'e rosins as starting material, the principles of .our inventioncan also be applied to a combination process for effecting polymerization and refining process prior to any heat treatment, has no subof starting rosins containing oxygenated mate'- rials, such as FF 'or intermediate grades of Wood rosin.

The following example will serve to illustrate of the Schnorf. Patent No. 2,074,192 by a complete absence of any zinc compounds and also by the fact that it has an acid value substantially as high as that o f the starting rosin, whereas Schnorf specifically states that his product contains traces of a metallic chloride and has a lower acid value than tthe starting rosin. The

patent to Morton No. 2,017,866 also particularly refers to a drop of from 10 to 20% in the acid value after polymerization. The product of our stantial drop in acid value. As a typical example, arosin having initially an acid value of 168 may be processed in accordance with our .invention to produce a partially polymerized rosin having 'minerales'- longA reaction timeis employei" "Another distinction between* the. process 'oi'| the Schnorfpatent. andthat-Qi' our invention ',resides'in'the Atreatment of the partially polymerizedrosin product result/ingl from the poly-'f` in a .petroleum solvent of bollini point'between 105 and 140' C.'in the presence of anhydrous T orf Patent lflo.. 1 2,074,192.41 amount of 'colorfdegradation takes place,- whereas there -i s no degradation in color .in vour processjexceptwhere anlextremely f merization step; Wehave'combined the partial' .1' 'polymerization stei with a heat trea tmentj 'step to increase the formation.' of dehydro and .dihydro' abietic'acil in thero'sin product and at-the :Sametime improve i-tsigrade. 'l

We are aware that numerous detailsQof the process-may be varied through af wide range without departing `i'r'om the principlesof -this invention,.- and` we therefore do not purpose zinc chloride to..agtemperature' under; the boiling* point or said solution until the 'desired 'degree of polymerization is obtained, washingsaidsolution with acidifled water and plain. water untiliree .,from 'zinc compounds, and. recoveringthe polymerized/rosi productfromthe solution.

9. The process ofprepar'ing a rosin product, which comprises Iorming-a solution or rosin in' angiziert organic solventqiree from more thairthe merest trace 'oi water. addingfan- 'hydrous zinc chloride .tosaid solution'. heating 4said solution at a temperature such as to efie'ct limiting. thejpaftent granted hereonotherwise than necessitated .by the' priorpart;

We'claimas our invntionz- P nl1. In the process ofpreparinga polymerized rosin, the step o1' heating at least a 50%.so1ution o`i' rosin to a temperaturenot verabout`145 C.

in .a solvent chemically inert to zinc 'chloride and inthe presence oi' zinc chloride under anhydrous conditions and maintaining such conditions throughout the 'entire heating step.

'A au but 4'rosin product by heatingrosin insolutionjn the genate and hydroge'nte'said rosin to produce a' presencev of anhydrous zinc chloride, the prelimpolymerized 'disproportionated rosin product o i the rosin solution from all j the rosin solution and. removing water from the 40 slvent distillate 'so 'formed until not more than arnere trace ct walter isleft in said solution.

4. In the process of preparing a. polymerizedrosin product by heating pale' Wood rosin d issolved in an4 inert 'organiosolvent in the presence 45 vent in the presence of zinc chloride.

of anhydrous zinc chloride, rthe step of removing the merstI trace of water from the solution-'oi said rosin in said solvent prior to heating saidso'lution in the presence of zinc chloride to prevent substantial color 'degradation 'of said 50 and having an acid number substantially the rosin-duringpolymerization.

5. Theprocess yof preparing a polymerized rosin product, which comprises heating an anhyf drous solution of rosin in an inertorganic sol- 6. The process y of preparing a polymerized rosin product, which comprises heating an anhy Y drous solution oi' pale rosin in an inert organic 'solvent in the presence of zinc chloride and polymerization orsaid rosin without' introducing water into' saidsoiution andsprating the polyA merizedirosin "from said solvent and any zinc compound including Isaid'zinc-chloride.

10. The process oi treating rosin,-wl;iich yconiprise's heating under anhydrous conditions'a' soution of rosin dissolved in an inert organic sol' ent and in thejpresexicA of zinc chloridevto sie ,multaneosly polymerize andadehydrogenate land hydrogenate said rosin to produce a polymerized dlsproportionatedl rosin product and recovering said rosin product free fromfany zinc compound.

' 11. The process/of treating' rosin. which comprises heating under anhydrous conditions a so'- lution of pale wood rosin dissolved in an inert orf o ganic solvent and inthe-presence oizinc 'chic-f ride to simultaneously polymerize and dehydroand for a suiilciently long period of time to ei'- Iect a simultaneous polymerization, dehydrogenf i ation -and hydrogenat'ion of said rosin. Washing said lsolution with acidified and plain water to remove all inorganic elements and .compounds and recovering the polvmerizedfdisproportionat-` ed rosin product entirely free of zinc compounds same as and a melting point substantially higher than the original rosin.,

13. The method .of polymerizing rosin, which comprises subjecting rosin in solution 'under anhydrous conditions tothe action` of zinc chloride v 'and heat at a temperature under 145 C.- for a maintaining anhydrous conditions in the re'sult-V s0 ing' reaction mass until the desired degree of polymerization is' obtained to prevent any sub- 'sufiicient lengthoftlme to eiect the desired degree of polymerization of said'rosin, washing said solution free from zinc and chlorides, and steam,

distilling on the rosin solvent to recover directly stantial degradation in color from that ofthe original pale rosin.

'1. The process of 4preparing a polymerizeds rosin product of l pale color', which comprises heating an anhydrous .solution of pale wood rosin in a petroleum solvent of boiling point vbetween 105 and 140 C. in the presence of anhydrous zinc chloride to -a temperature under the boiling point oi' said solution until the merization is obtained. 8. 'I'he "-processo! preparing a polymerized rosin product of'pale color, which comprises desired degree of polyheating an anhydrous solution oi pale wood rosin 75.

a polymerized rsin product having. a substan- ,tially .higher melting point than the original' rin. A

14, The method of polymerlzing rosin, whichcomprises subjectinga heat treated pale .Wood rosin in a solution of at least 50% rosin concentration by weight under anhydrous conditions to' the action'of zinc chloride'and heat at a temper'. ature"under'145 C. for a suiicient length of time to effect the desired' degree ofpo1ymenzation 'or said rosin, washing said solution free from zinc and chlorides, and steam distilling oi the rosin solvent to recover directly a polymerized rosin I subjecting .said rosin 'to the action of heat and zinc chloride, the step oi removing zinc from the pale rosin dissolvedl in an inert solvent in the 15. The method'ot preparing disproportionated rosin from rosin which has already been subjected to-the action ot heat and zinc chloride under anhydrous conditions .to Dolymerize, dehydrogenate and hydrogenate said ros- A a polymerized in, which comprises heating such previously treated rosin between 250 and 300 C. for a sumcient length oi' time to'further dehydrogenate and hydrogenate the same.

18. In the method of polymerizing rosin by polymerized rosin product which comprises washing said product with an' aqueous solution of an acid stronger than ahieticacid until all of the zinc is dissolved in said solution and recovering the polymerized rosin product. A 17. The method of increasing the melting point of rosin without appreciable loss of acid value or degradation of color, which comprises heating presence of zinc chloride under anhydrous conditions until the desired amount of polymerization has occurred, washing the reaction mass withan aqueous solution oi an acid stronger than abietic to remove all zinc from the polymerized rosin "product and recovering said product free oi solvent.

18. 'I'he method of increasing the melting point of rosinV which comprises heating pale rosin dissolved in an inert solvent in the presence of zinc chloride under 'anhydrous conditions until the' desired amount of polymerization has'oocurred. washing the reaction mass with'an aqueous solution of an aci/d stronger than abietic to remove al1 zinc from the polymerized rosin product, re-

covering said product free of solvent, heat treato ing 'said product at Z50-300 C., vacuum distilling said product to remove lower melting point con- A high melting point polymerized rosin product'remaining after such distillation.

19. The .method of increasing the melting' product having' a; .substantiallyhigher melting. point'than'the original rosin'. f

-point` oi rosin. without appreciable'loss o! acid value or degradation 'of color, which comprises heating pale rosin dissolved in an inert solvent in the presence' o1' zinc' chloride ,under anhydrous conditions until thedesired amountl oi polymerization has. .o ccurred. washing; the naction mass .with an/agueous solution of an acid st onger than abietic to remove all zinc from the polymerized rosin product, recovering said product tree of solvent, heatrtreating s'aid product at '250300 C., Avacuum iractionating saidproduct to remove lower melting point ,constituents 'therefrom' and ,Y separating a. pale high` plus rotation rosin until only non-distillefbie substantially dibasic rosin acid having a pale 'color and acapillarytube melting point of at least as high as 110 're` v mains and recovering the same.

2'0. 'Ihe method 0I DOlYmerizing and refining ldark wood rosin, which comprises subjecting dark wood rosin in an inert organic solvent solu' ,polymerized 'rosin from -said-v solution free from all zinc compounds and lighter in col'or than the .original rosin.

21. The method of polymerizing and refining dark wood rosin, which comprises subjecting dark v `wood rosin'in an inert organic solvent solution having a co'ncentrationIof at least 50%rosin by weight under anhydrous conditions to the action of heat and-zinc chloride until polymerization 4has progressed to the desired extent, diluting the -resultin'g solution toeiect the precipitation of stituents therefrom and recoveringthe resulting rnigre therefrom, recovering thedpartially polymerized rosinfrom said solution free from all' zinc compoundsand lighter in color than the original rosin and subjecting said partially polymerized rosin to the action of fullers earth to remove color bodies therefrom. ROBERT C. PALMER.

' cARmsLn H. BIBB.

DISCLAIMER massa-Rober: Q. Palmer'. and Carlisle H. Bib, Pensac'ola' F18;a METHOD or anc dated July 1 PoLYMERrzIING R'osIN AND PRoDUc'rMAE Truzr'nmar.v A.11941. Disclaimerlled- August 2, 1943, By the assignee, Newport Induste, no'. 'A .-1. '1". v\'

Hereby enters this disclaimer to claim 16 in s aid speifcatn.

[Qjcz'al Gazette August 31, 1943.] 

